Lubricant compositions



' Patented Mar. 20, 1945 LUBRlOANT COMPOSITIONS Herschel G. Smith, Wallingiord, and Troy L. Cantrell, Lansdownc, Pa., assignors to Gulf Oil Corporation, Pittsburgh, Pa., 9. corporationoi Pennsylvania No Drawing. Application Januar 26, 1944,

' Serial No. 519,810

7 Claims. (Cl- 252-51) This invention relates to improvements in lubricant compositions; and more particularly to light lubricating oil compositions of the-type known as household lubricants.

Household lubricants are low viscosity oils intended for lubricating electric fans, guns, and all sorts of light mechanism with exposed surfaces of steel, copper and other metals. 1 In general, such oils are applied and used as a more or less stationary film to protect surfaces exposed to the atmosphere. Plain mineral oils under such conditions do not afford adequate protection against rust or corrosion or both and are open to other objections. Various mineral oil compositions have been proposed, containing to blend the several agents together before adding them to the lubricating mineral oil. These particular agents will blend together without mutual deleterious eflects, and the resulting composition is readily blended with oils.

1. The rust inhibitor is advantageously an amine salt of isoamyl octyl acid phosphate, prepared by bringing into reaction isoamyl octyl acid phosphateand so-called' cocoamine, which is a commercially available material prepared by converting cocoanut oil fatty acids into the corresponding amines. It consists mostly of monolauryl amine. CH':(CHa)m-CHz- NH:, with misubstances intended to overcome the limitations of plain mineral 011. None has proved" entirely satisfactory. It is difllcult to prepare a compounded oil containing a plurality of agents each intended to perform a specific function while not interfering with the others, and many compounded oils show a tendency to discolor or deposit insoluble matter on long standing. This is especially true of fatty oils, particularly castor oil.

One object of the present invention is the 'provision of a household oil composition which has excellent lubricating properties, which is itself non-corrosive, inert and insensitive to moisture, air, etc., and which has the property of protecting steel and other metal surfaces from rust and other forms of corrosion, even on long exposure to adverse atmospheric conditions; and the provision of such an oil which is clear and light in color as prepared and which even on long standing remains bright and clear without development of haze, sediment or discoloration.

These and other objects are achieved by the provision of a lubricating oil composition, the base of which is a light, highly refined mineral oil of viscosity about 60 to 150 seconds SUV at 100 F.; loo-second oil being especially advantageous. In such an oil are dissolved or blended minor amounts of (1) an amine salt of an organic phosphate, as a rust inhibitor, in amount suflicient to protect steel surfaces from rust when filmed with the composition; (2) an oil-miscible castor oil to serve as an oiliness agent; (3) a refined sperm oil ester. or its equivalent asa gumresistant oiliness agent and stabilizer for the eastor oil; and, (4) an oil soluble anti-oxidant.

In preparing our household oil, if desired, each agent can be separately and directly added to the lubricating oil base, but it is more convenient nor amounts of adJacent homologues. In preparing the rust inhibitor, the reaction between the, amine and the acid phosphate is so controlled as to bring the pH of the product within the range 5.5 to 7.5. This inhibitor is disclosed in our co-pefiding application, Serial No. 420,438, filed November 25, 1941, and, as disclosed in that application, other amines besides cocoamme can be employed, all belonging to the'class of primary fatty amines containing from 8 to 18 carbon atoms. These amines include mono-.

capryl amine, CHa(CHa)sCH2NHz, mono-lauryl, mono-mynstyl, monopalmityl and monostearyl amines. In lieu of this class of inhibitors there can be employed, also with advantage, the reaction product of isoamyl octyl acid phosphate with di-cyclohexyl amine in approximately equi-' molecular proportions and adjusted to a vpH; within the range 5.5 to 7.5 as described in our co-pending application, Serial No. 420,439, filed November 25, 1941.

Asshown in our prior applications, Serial Nos. 420,438 and 420,439, such rust inhibitors are readily soluble in mineral oils and mineral oil solutions thereof, effectively protecting metals against rusting and corrosion when applied thereto. In. the present invention we get along with less of this rust inhibitor than would otherwise be necessary by virtue of the presence in our improved composition oi ingredients 2 and 9 (see below).

protection were they relied on alone. But their effect, in the proportions indicated, is cumulative with that of the aminophosphate to impart 2. The oiliness agent is, as stated, a mineraloil-miscible castor oil. Castor oil, itself, is not miscible with mineral oils, but it can be processed in known ways to render it oil-miscible. In

These last have some anti-rust properties, but not enough to aflord adequate as regards steel-to-steel lubrication and lubri-.-

cation of steel in'contact with bronu and other metals. Thus it contributes to the wide range of utility of our oil composition.

While this oil soluble castor oil is excellent as an oiliness agent, it has a tendency to develop insoluble matters or haze in the course of long standing. We effectually restrain, this tendency by incorporation of ingredient no. 3, the monohydric alcohol fatty acid ester. u

3.. The gum-resistant oiliness agent is advantageously a substantially pure sperm oil ester, free from water and glycerides. This substance was'very resistant to oxidation and gumming. Furthermore, in our composition it serves as an excellent solvent or blending agent; it facilitates the preparation of concentrates with the other ingredients, andit prevents development of insoluble matter, haze, sediment, etc. on long standing which might otherwise occur due to the presence of the modified castor oil. Only a small amount of the esters is necessary, suflicient to prevent this last-mentioned effect, in view of the presence of the partially dehydroxylated castoroil which is itself an excellent oiliness agent. In lieu of sperm oil or other fatty mono esters which are essentially oleic acid esters of long chain monhydric alcohols, we can employ similar fatty acid esters of short-chain monohydric alcohols: e. g. ethyl oleate, butyl oleate, butyl, stearate and ethyl thiostearate.

4. The fourth ingredient. an oil-soluble antioxidant, to retard the formation of oil acids, is a tertiary alkyl phenol anti-oxidant such as that prepared by alkylating a phenol with refinery gas: see U. S. Patent 2,149,759 issued March 1939, to T. L. Cantrell. Examples oi" this class of material are 2.4,6-tri-tertiary butyl phenol, and 2,6-di-tertiary butyl-para cresol. These oxidation inhibitors are among the few that can be employed in the proportionsindicated without developing insoluble matters or darkening in color. They serve as additional stabilizing agents and solvents for the modified castor oil. The-mineral oil, itself, is fairly stable, butwhen' there is added an oiliness agent such as par: tially dehydroxylated castor oil, a compounded oil containing this materialwill more readily compounded with refined lubricating oil of 100 viscosity, SUV, at 100 F., as follows:

The above oil composition exhibits the following properties:

Gravity APL- 28.8 Viscosity, SUV: 100 F. 103 Flash, 00 F 335. Fire, 0C F..- 375 Corrosion test (see below): Duration of tests days 12 Temperature F.. 122 Test strip (see below):

Steel Passes (no corrosion) Copper Passes (no corrosion) Air rate -..cc./hr-- 2000 Water added per cent 10 Salt (3.39%)

In determining the protective properties of our improved oil com-positions ante, ,a drastic test was employed which comprises immersing a steel strip in 36 cc. of oil in a test tube and adding thereto 4 cc. of sea water placing the assembled tube in a water bath controlled at 122 F. and passing 2000 cc. of moist air per hour into the tube at a point near the bottom to mix the oil and water. This testis conducted for 12 days and make-up water is added each 24 hours to maintain the level of water.

In the example ante, the steel test strip in the presence of uncompounded base oil showed rust within 6 hours, whereas the steel strip in the compounded product showed no rust within 12 days. Tests with strips of other metals, e. g. copper, gave similar good results.

In the above example, the proportions of the additive agents incorporated in the mineral oil may be varied, if desired as shown in our prior application, Serial No. 422,008.

In general, as disclosed in our Serial No. 422,- 008, the optimum ranges of proportions for the several constituents are as follows:

I Per cent Base oil 98.5 to 99.75 Rust inhibitor 0.05 to 1.0 Oil-miscible castor 'oil 0.05 to 1.0 Gum-resistant oiliness agent 0.10 to 1.0 Oil-soluble anti-oxidant 0.05 to 0.5

As there shown, such improved lubricants have manyadvantageous properties and are particuoxidize with development of insoluble matter, a

if some oi this type oxidation inhibitor is not present. Thus in the present invention we add the oil oxidation inhibitor to counterbalance the defects that might otherwise be encountered from the oil-soluble castor oil.

In our prior application. SerialNo. 422,008, filed December 6, 1941, we have broadly described such improved oil compositions and household lubricants and methods of preparing the same from the several ingredients set forth ante. As there described. one good example of a composition within the purview of this invention is 15 5.5 and 7.5.

larly useful in protecting. metals from rust and corrosion as well as eflectively lubricating the same.

The present application is a 'continuation-inpart of our prior application, Serial No. 422,008 died December 6, 1941. In turn, our application, Serial No. 422.008 is a continuation-in-part of our earlier co-pending application, Serial No. 420,439, flied November 25, v1.941.

In our prior application, Serial No. 420,439, we

. have also disclosed improved lubricating oil compositions containing, as a rust inhibitor, a substantially neutral reaction product obtained by reacting isoamyl octyl acid phosphate with dicyclohexyl amine in approximately equimolecular proportions under such conditions that the reaction product or mixture has a pH between acunae The acid phosphate employed as one reactant is a di-ester of ortho-phosphorlc acid This compound is also known as 3-methyl-butyl, Z-ethyl-hexyl ortho-phosphate.

The other reactant, di-cyclohexyl amine is likewise a well-known chemical compound, commercially available as a .substantially pure material; though it is not necessary that a CP" amine be used. One of the commercial grades advantageousjor the present purposes has the following properties:

The reaction between di-cyclohexyl amine and the acid phosphate ester is exothermic and as described in our prior application, Serial No. 420,439, the temperature is controlled by heating or cooling as required in preparing our rust inhibitors from said amine and phosphate ester by the method set forth in that application. Further, as there described, the reaction products so obtained are substantially neutral. They are relatively stable compositions under ordinary conditions. At room temperatures, they are V .3 3 to 4 and the final adjustment and control of the pH value is then effected. In doing so we add 18 pounds of the amine and the mixture is maintained at approximately 165 F. until it has a pH of approximately 7.2.

. The rust inhibitor so obtained is a heavy 'viscous, oily liquid.- Similar viscous oily rust inhibitor can be readily obtained having other pH values within the range of 5.5 to 7.5 by controlled heavy, viscous, oily liquids. They are relatively thenic type mineral oils dissolve somewhat larger amounts.

Accordingly the rust inhibitors described in our application, Serial No. 420,439 are advantageous in preparing improved household lubricants, particularly those containing various fatty oils compounded with the mineral oil, as further described in that application.

The following examples illustrate advantageous methods of preparing these rust inhibitors and improved oils and lubricants containing the same 1 Example I .-In preparing this particular rust inhibitor, the reaction is carried out in an iron kettle equipped with means for heating and cooling and for agitating the mixture. Into the kettle are introduced 181 pounds of commercial dircyclohexy'l amine, and 281 pounds of cominercial isoamyl octyl acid phosphate are gradually added with stirring. The reaction is vigorous and quite exothermic and the acid phosphate is'added at such a rate as to facilitate maintaining the reaction temperature below 180 F. The mixture maybe cooled if required to maintain it below that temperature. action temperature isbest maintained between 140 and 180 F. during the larger portion of the reaction. After all of the acid phosphate has been added, the mixture is ordinarily warmed to facilitate completion of the reaction. At this time the reaction mixture usually has a pH of The readjustment of the pH during the last stage of the reaction.

The product of this example is sufliciently soluble in mineral oils for making the improved oil compositions in this invention. As the amine, from which the above rust inhibitor is prepared, is also soluble in mineral oils, we sometimes prepare the oily rust inhibitor in situ in the mineral oil. In such embodiments of this invention, the

di-cyclohexyl amine is first dissolved in the mineral oil and then the acid phosphate ester added, the mixture being stirred and maintained at the desired temperatures until the reaction is complete and the mixture adjusted to the proper pH value, the added mineral oil serving as a diluent, facilitating control of the reaction. The concentrates or oil solutions of neutral reaction products so obtained are useful addition agents to various types of lubricants. The preparation of such concentrates is illustrated in the following exat 100 F. were added to an iron vessel equipped with means for heating and cooling and agitation. The initial temperature of the oil was F. To this oil were added 181 pounds of di-cyclohexyl amine, which was thoroughly mixed with the oil by mechanical agitation and the final temperature of this mixture was 82 F. To the oil-amine mixture 281 pounds of commercial isoamyl octyl acid phosphate were'added over a period of two hours, during which time the temperature of the reaction mixture rose to 188 F. After stirring for one hour, the pH of the mixture was 3.7. In order to increase this value to the desired range, nine pounds of di-cyclohexyl amine were added to the mixture and stirred, and the resultant mixture had a pH of 6.2. To secure a final adjustment, nine additional pounds of di-cyclohexyl amine were added to the mixture which after stirring for one hour and cooling to room temperature, exhibited a pH of 7.4.

The oily mixture prepared in this Example II can be regarded as a sort of concentrated stock solution, which can be stored indefinitely and incorporated in lubricating oils as desired to prepare commercial anti-rust oils, etc.

Example III.-A household-type lubricating oil was prepared by dissolving 0.05 per cent by weight of di-cyclohexyl amine isoamyl octyl phosphate, prepared as in Example I. Properties of the new oil and the base oil are tabulated below:

Inhibited 011 Base oil Gravity, A. P. I 28.9 28.9 Viscosity S. U V.-

1 101.4 100.7 210 38. .38. 6 335 3% 00 F 380 385 Pour, 1 40 --45 Color, N. P. A. 1.25 l. 25 Carbon residue per cent 0 02 Trace Neutralization o 0:06 .0. 03 Corrosion test:

Steel strip Passes Fails Copper strip- Passes Fails It is sometimes desirable to incorporate oiliness agents and extreme pressure agents in rustpreventive oils; agents such as sperm oil and castor oil which have been processed torender them miscible with mineral oils. According to the present invention, a concentrate can be prepared, in-

cluding the new rust inhibitor together with oil= Materials Pounds I Sperm nil 80 Oil-soluble castor oil 2 Reaction product from Example I. 2,4,0-tri-tertlary butyl phenol 20 The oil-soluble castor oil used in this example was a partially dehydroxylated castor oil which is readily soluble in mineral oils and is available as a commercial material. Likewise, the sperm oil employed was a commercial oil substantially free of glycerides. The properties of the commercial sperm oil and oil-soluble castor oil were as follows:

Oil-soluble cast), on Sperm oil Gravity, A. P. I l6. 7 Sp. gr. 60l60 F 0. 9548 0378-0384. Viscosity S. U V

100" i 1, 328 95-110. 210 F 142.9 Flash, 00, F 485 Min. 400

ire, 00 F 600 Pour, I Max. Color, N. P. A 2.25 Not darker than 3.0. Carbon residue, per cent 0. 48 Neutralization No 3. 20 Max. 2.0. Oleic acid equivalent per cent. Max. 1.0. Iodine No. (modifie Hanus). 103.8 -90. Saponification No 190. 4 -140 In blending these oils with the rust inhibitor and antioxidant, the procedure was as follows: The sperm oil was introduced into the kettle and the oil-soluble castor oil gradually added with stirring. The mixture was maintained at a temperature between 60 and 70 F. and the agitation continued until a clear blended oil was obtained. To the blended oil, while continuing the agitation, were added the reaction products from Example I which rust inhibitor readily dissolved in the blended oil. Then the 2,4,6-tritertiary butyl phenol was added with agitation and the temperature was brought to F. and held at that temperature until a homogeneous blend was obtained. The warm mixture was then passed through a filter press to'remove any traces of insoluble matter. The filterate so obtained was a clear oily fluid which can be stored indefinitely. It is readily soluble in oil and requires no special blending procedure to incorporate it in mineral lubricating oils in making our improved lubricants. The preparation of one castor oil and 0.1% to 2,4,8-trl-tertiary butyi phenol. l q

The properties of the improved household oil as compared with those of the mineral oil alone are tabulated below:

Inhibited Uninhibltsd oil base oil Physical ropertles:

GravRy,API 33.5 33.6. Viscosity SUV- 100 1% 1049-- 105.0. 21 39.7 10.0 Flash, ()0 F 37 370 Fire,0 F 430 430 Pour, "F 0 0 Color, Saybolt.. +16 Carbon residue percent... 0.01-- 0.01 Neutralization o 0.20... 0.02 Tests:

Corrosion test- Steel strip Passes Fails. Copper strip do Do. Evaporation loss, copper dish,

percent- 212352, 5 g., 48 hr{. a r 0 d ppearanceo cup o0 Sludge N Nil. Falex wear test- 500 lb. jaw load, 15 mm.

wear: No. of teeth 1 l Fails. Sligh oxidation N 0 R 5. Oxdation test: 8. H. Kress o.-

Gopper strip test, appearence Medlumstaiu. Light stain.

Oxidized 0i1 Color, NP 5.0- r 1.0. Neutralization No 0.20 0.01. Sludge, percent Nil... Nil.

1 One tooth wear is equivalent to 0.00002 wear on the test shaft and block.

In the above example, the steel test strip in the presence of the uncompounded base 011 showed rust within 6 hours, whereas the steel strip in the uncompouncled lubricant showed no rust in 12 days. Tests with strips of other metals, e. g. copper, gave similargood results.

The oiliness properties were evaluated with the aid of a Falex tester, a device making use of a shaft rotated between two well-machined test pieces to which controlled pressure may be applied. Measurement of the wear was made at the end of the test. The improved oil shown in the example in this test developed a wear of only 14 teeth, whereas uncompounded oil failed to carry thetest load. In order to evaluate the anti-gumming properties, 5 grams of oil were heated in a copper dish at 212 F. for 48 hours and the sludge and gum deposits inspected. Our

, improved oil showed noevidence of gumming or sludge deposits.

The foregoing specific examples are merely illustrative of certain advantageous embodiments' of this inventiom and various other com mercial embodiments may be employed in the generic practice thereof. For instance, in preparing concentrates or blends of the several agents, as illustrated in Example IV ante, we sometimes employ, in lieu of the reaction products produced in Example I, the concentrated solutions thereof in mineral oil such as produced in Example II; the concentrated solutions of rust inhibitor in mineral oil being completely miscible with thesperm oil and other agents set forth in Example IV. The blended oil compositions so obtained can be incorporated in a wide variety of lubricating oils to improve their rust preventive and lubricating properties. These blends or composite improvement agents comprising a blend of mineral oil,-rust inhibitor, oiliness'aud anti-oxidant agents are usetul and advantageous in preparing improved household oiliness and other commercial lubricants. In general, a widevariety of improved lubricatingoils and compositions can be prepared in accordance with this invention as described and illustrated ante.

- What we claim is:

1. An improved petroleum oil composition, effective as a lubricant for ferrous and non-ferrous 'metal surfaces and capable of preventing rusting and corrosionthereof in the presence of moisture and air, comprising a mineral lubricating oil containing 0.05 to 1.0% of, a partially dehydroxylated castor oil, 0.l to 1.0 per centof a fatty monoester, 0.05 to 0.5 per cent of a teraddition. product of di-cyclohexyl amine and 3- 2. The improved composition of claim 1 wherein said fatty monoester is sperm oil.

3. The improved composition of claim 1 wherea in said fatty monoester is butyl oleate.

4. The improved composition of claim 1 wherein said fatty monoester is butyl stearate.

5. The improved composition of claim 1 wherein said tertiary alkyl phenol is 2,4,6-tri-tertiary butyl phenol.

6. The improved composition of claim 1 wherein said tertiary alkyl phenol is 2,6-di-tertiarybutyl paracresol.

7. An improved petroleum oil composition, effective as a lubricant for ferrous and nonferrous metal surfaces and capable of preventing rusting and corrosion thereof in the presence of moisture and air, comprising a mineral lubrieating, oil containing 0.1 per cent of a partially dehydroxylated castor oil, 0.3 per cent of sperm oil, 0.1 per cent of 2,4,6-tri-tertiary butyl phenol methyl-butyl, 2-ethyl-hexyl acid hosphate, dissolvedthereln, said substantially neutral prodnot containing the said acid phosphate and amine phenol being 2,4,6-alkyl phenol containing at least one tertiary butyl group andbeing capable of inhibiting the oxidation of the partially dehydroxylated castor oil, the said fatty monoester being an ester of a fatty acid and a monohydric alcohol and being capable of preventing development of insoluble matter in said composition, all of the said agents being mutually soluble and miscible in the proportions specified and. the soblended composition being a stable, clear, homogeneous solution of said agents in the mineral oil,.the said 011 solution thereof having excellent oiliness and other lubricating properties on both ferrous and non-ferrous metals, being non-corrosive to such metals, being inert and insensitive to moisture and air, and being free from discoloration, development of haze. and depositlon of insoluble matters.

chemically combined together in molar ratios between 1:1 and 1:1.1 and having a pH between 5.5 and 7.5 and being capable of inhibiting the corrosion of said metals in the presence of air and moisture, said partially dehydroxylated cashaze and insoluble matters and stable against tor oil being readily soluble inthe mineral oil but havinga tendency to oxidize and develop insoluble matter, said 2,4,6-tri-tertiary 'butyl phenol being capable of inhibiting the oxidation of the partially dehydroxylated castor oil, the sperm oil being capable of preventing the development of insoluble matter in said composition. all of said agents being mutually soluble and miscible in the proportions specified, and the so-blended com-position being a stable, clear, homogeneous solution of said agents in the mincm] oil.

- HERSCHEL G; SMITH.

' TROY L. CANTRELL. 

